Introduction

Coulomb interaction is the electrostatic interactions between electric charges, and follows the Coulomb's law, which is a basis of classical electrodynamics. In general, Coulomb interaction can manifest itself on various scales from microscopic particles to macroscopic bodies. The microscopic theory of Coulomb interaction has been developed in the frame of quantum field theory.

Basic formulae

The electrostatic interaction of two point charges <math>q_1</math> at position <math>\mathbf r_1</math> and <math>q_2</math> at position <math>\mathbf r_2</math> is described by the Coulomb's law:

where <math>\mathbf F</math> is the electrostatic force experience by <math>q_1</math> (solely) due to the presence of <math>q_2</math>, and <math>\epsilon_0</math> is the vacuum permittivity, which has a value of <math>8.85\times10^{-12}</math> approximately.

Coulomb interaction obeys the principle of linear superstition, and therefore the force on a point charge exerted by a object with continuous charge distribution is give as